1. Field of the Invention
The present invention relates to a power transmission system comprising a hydrostatic continuously variable transmission constituted by integrally and coaxially coupling a pump cylinder of a swashplate type hydraulic pump with a motor cylinder of a swashplate type hydraulic motor, the continuously variable transmission being rotatably supported at its opposite ends on a bearing, a first transmission device connected to an engine and to an input member of the hydraulic pump from one side of the continuously variable transmission, and a second transmission device connected to a load member and to an output member of the hydraulic pump from the other side of the continuously variable transmission.
2. Description of the Prior Art
Such power transmission system has already been known, as disclosed, for example, in Japanese Patent Application Laid open No. 224769/87.
In the above prior art power transmission system, however, the first and second transmission devices are connected to the opposite ends of the continuously variable transmission, respectively and hence, large radial loads in the opposite directions act on the continuously variable transmission from both of the transmission devices. Due to this action, a large swinging moment is produced in the continuously variable transmission. Particularly, the swinging moment is large, and the load on the bearing is correspondingly large, because the continuously variable transmission is of a type having the pump and motor cylinders integrally coupled to the output shaft.